<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>超链接</title>
</head>
<body>
    <h1>This is heading 1</h1>
    <h2>This is heading 2</h2>
    <h3>This is heading 3</h3>
    <h4>This is heading 4</h4>
    <h5>This is heading 5</h5>
    <h6>This is heading 6</h6>
</body>
</html>